The present invention relates to digital rights management. Software applications for reading or writing electronic documents often come in multiple versions. A cheap or free version of the software application with limited functionality can be used to view electronic documents, for example, on a computer screen. One example of such a free software application is the Adobe® Acrobat® Reader®, manufactured by Adobe Systems Incorporated, San Jose, Calif., which allows a user to read PDF (Portable Document Format) documents.
In addition to the limited functionality software, the same vendor may also provide a feature-rich premium version that allows users to create and manipulate electronic documents in ways that are not provided in the limited functionality version. For example, the Adobe® Acrobat® application also manufactured by Adobe Systems Incorporated, allows a user to work with PDF documents and perform operations such as filling in and saving a form, digitally signing a form field, adding comments, and performing other operations. Currently, the only way for a document user to access these types of features is to buy the premium version of the software.